platform_system_sepolicy/public/update_engine.te
Nick Kralevich 5e37271df8 Introduce system_file_type
system_file_type is a new attribute used to identify files which exist
on the /system partition. It's useful for allow rules in init, which are
based off of a blacklist of writable files. Additionally, it's useful
for constructing neverallow rules to prevent regressions.

Additionally, add commented out tests which enforce that all files on
the /system partition have the system_file_type attribute. These tests
will be uncommented in a future change after all the device-specific
policies are cleaned up.

Test: Device boots and no obvious problems.
Change-Id: Id9bae6625f042594c8eba74ca712abb09702c1e5
2018-09-27 12:52:09 -07:00

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# Domain for update_engine daemon.
type update_engine, domain, update_engine_common;
type update_engine_exec, system_file_type, exec_type, file_type;
net_domain(update_engine);
# Following permissions are needed for update_engine.
allow update_engine self:process { setsched };
allow update_engine self:global_capability_class_set { fowner sys_admin };
# Note: fsetid checks are triggered when creating a file in a directory with
# the setgid bit set to determine if the file should inherit setgid. In this
# case, setgid on the file is undesirable so we should just suppress the
# denial.
dontaudit update_engine self:global_capability_class_set fsetid;
allow update_engine kmsg_device:chr_file w_file_perms;
allow update_engine update_engine_exec:file rx_file_perms;
wakelock_use(update_engine);
# Ignore these denials.
dontaudit update_engine kernel:process setsched;
dontaudit update_engine self:global_capability_class_set sys_rawio;
# Allow using persistent storage in /data/misc/update_engine.
allow update_engine update_engine_data_file:dir create_dir_perms;
allow update_engine update_engine_data_file:file create_file_perms;
# Allow using persistent storage in /data/misc/update_engine_log.
allow update_engine update_engine_log_data_file:dir create_dir_perms;
allow update_engine update_engine_log_data_file:file create_file_perms;
# Don't allow kernel module loading, just silence the logs.
dontaudit update_engine kernel:system module_request;
# Register the service to perform Binder IPC.
binder_use(update_engine)
add_service(update_engine, update_engine_service)
# Allow update_engine to call the callback function provided by priv_app.
binder_call(update_engine, priv_app)
# Read OTA zip file at /data/ota_package/.
allow update_engine ota_package_file:file r_file_perms;
allow update_engine ota_package_file:dir r_dir_perms;
# Use Boot Control HAL
hal_client_domain(update_engine, hal_bootctl)
# access /proc/misc
allow update_engine proc_misc:file r_file_perms;
# read directories on /system and /vendor
allow update_engine system_file:dir r_dir_perms;